A Proximity Service (ProSe) refers to a scheme that supports communication between devices located physically close to each other. Specifically, ProSe is aimed to discover an application operating in devices that are in proximity to each other and ultimately to support an operation of exchanging application-related data. For example, it may be considered that ProSe is applied to applications such as Social Network Services (SNS), commerce, and games.
ProSe may also be called Device-to-Device (D2D) communication. That is, ProSe refers to a communication scheme for establishing a direct link between a plurality of devices (e.g., User Equipments (UEs)) and thus directly exchanging user data (e.g., voice or multimedia data) between the devices without passing through a network. ProSe communication may include UE-to-UE communication, peer-to-peer communication, etc. In addition, the ProSe communication scheme may be applied to Machine-to-Machine (M2M) communication, Machine Type Communication (MTC), etc. Therefore, ProSe is being considered as one solution to burden of an eNodeB due to data traffic that rapidly increases. By introducing ProSe, effects such as reduction in procedures of the eNodeB, decreases in power consumption of devices that participate in ProSe, increase in data transmission rate, increase in network accommodation capacity, load distribution, cell coverage expansion, etc. can be expected.